High-voltage primary cut-out



Dec. 11, 1928. 1,694,979

E. G. NEWTON ET AL HIGH VOLTAGE PRIMARY CUT-OUT Filed April 21, 1925 2 Sheets-Sheet 1 Fig. L

Fig.2.

g lfz/ 26 g 4 g Inventors Edward G Newton ElmerJ. \X/cde,

Their Attorneg Dec. 11, 1928. 1,694,979

E. G. NEWTON ET AL I HIGH VOLTAGE PRIMARY CUT-OUT Filed April 21, 1925 2 Sheets-Sheet 2 f" lug-ix a I I I Invent ols Edward G. Newton, Elmer J. Wade,

Their Attorneg.

Patented Dec. 11, 192

UNITED STATES 1,694,979 PATENT OFFICE.

EDWARD o. NEWTON AND ELMER .1. WADE, or rITrsrIEDD; MASSACHUSETTS, AS- sIGNORs T0 GENERAL ELECTRIC COMPANY, A CORPORATION or NEW YORK.

HIGH-VOLTAGE PRIMARY CUT-OUT.

Application filed April 21, 1925. Serial No. 24,837.

The present invention relates to distribution of electric power and more especially to high potential protective means for use out of doors and generally known as primary outouts.

The object of the invention is the provision of an improved primary cut-out which will function effectively under all weather conditions to interrupt electric circuits operating under several thousand volts potential and which will not deteriorate or become broken in long continued heavy service.

The invention is embodied in the construction shown in the accompanying drawings, in which Fig.1 is a front elevation of the stationary member of the cut-out; Fig. 2 is" a rear or inner side elevation of the movable member of the cut-out with an expulsion fuse shown in place thereon; Fig. 3 is a transverse section of the stationary member taken on line 3 3 of Fig. 1; Fig. at is a central vertical section of the cut-out and fuse in closedor operative condition; Fig. 5 is a similar View of the stationary member and an edge elevation of the movable member and fuse in detached or open condition; and Fig. 6 is a cross section of the enclosed fuse and posi tioning ledge taken on line 6 -45 of Fig. 2.

The stationary member of the cut-out consists of a box-shaped receptacle 1 made of a single piece of glazed porcelain and with massive and strong walls. The side walls 2 and 3 are each provided with two projecting rain shedding knobs 4 pierced by upwardly inclined wireentrance apertures 5 which entend therethrough to the interior of the receptacle for the entrance ofthe line wires. The frontedges of thesidenwalls 2 and 3 and the top wall 6 are provided with a rabbeted cornor 7, while the bottom wall 8 is provided with an outwardly flaring aperture 9 and two hinge brackets 10. The rear wall 11 is provided with two dovetail projections 12 and 13 for engagement with a sheet metal supporting bracket 14 secured thereto by a transverse bolt 15 which passes transversely through the dovetailed edges of the bracket and is t isplaced in the valley. 16 between the two projections. By this arrangement the metal. support serves also to reenforce the moulded insulation and without any holding part extending tl'irough the insulation wall. The top wall 6 has a Water sheddin overhang 17 and is transversely apertured or the reception of a latch bolt 18. Crossing the interior center of the receptacle are two integral spaced dams 19 provided with crescent grooves or notches 20 in their tops. In the respective compartments into which thein terior of the receptacle is divided 'by the dams 19 are metal terminal plates 21 secured (ill in place by set screws 22 engaging babbitt line wires are introduced through one side 1- wall or the other of the receptacle.

The movable member of the cut-out isin.

the form of a thick slab 27 of tough insulating compound having a projecting inner border 28 along both side and top edges to shut tightlybver therabbet projection 7 of the receptacle to prevent the entrance of rain water to thelatter. A raised panel 29 extends lengthwise the inner side of the slab 27 and is of a size to fit closely in the cavity of the receptacle, while the lower end extends be low the bottom of the slab 27 and carries hinge blades 30. About one-third of the longitudinal central portion 31 of the panel 29 is raised above the end portions 32 so that when the movable member is in closed position its surface will be in close proximity to the tops of the dams 19. The surface of the central portion 31 is provided with longitudinal groove 33 and on opposite sides there-- of with projecting battles 34 adapted toenter the valley between the dams 19. The end portions are provided with fuse terminal. positioning ledges 35 and fuse retaining means. The fuse retaining means on the lower end portion 32 is in the form of the usual bow clip 36, while the means on the upper portion 32 is in the form of a loop37 with an angle bracket 38 projecting outwardly. The front of the movable member is provided with a loop-39 for receiving the. end of the usual operating hook (not shown) The fuse is of the expulsion and con; sists of insulating barrel a0 pre at its Mid upper end with a metal ferrule ll. perms 43 is threaded for the reception of a knurled thimble 44. The barrel 40 is provided at its lower end with a metal sleeve 45 mounted thereon to swivel slightly by means of a set screw 46 entering part way of a transverse slot 47 cut .in the outer wall of the barrel and thereby providing a slight clearance between the point of the screw and the bottom of the slot as shown in Fig. 6. The upper contact part of the sleeve 45 is made cubical, while the lower part is threaded somewhat above the end and below the thread 48 is a cone 49, and knurled collar 50 having its inner surface provided with a complementary cone 51 is threaded therein.

The fusible element is in the form of a narrow strip 52 of soft metal or alloy having a disk-shaped head 53 at its upper end and an insulating sheath 54 of sheet asbestos surrounding the strip 52 up to very near its disk head but leaving a reduced section exposed at that point.

To insert the link strip 52 in the fuse the thimble 44 is removed and the free end of the strip threaded through the barrel 40 and drawn down until the head 53 seats upon the upper end of the ferrule 41; the thimble 44 is replaced and screwed home tightly to clamp the head 53 and make good contact therewith; the collar 50 is removed and the free end of the strip bent up over the end wall of the barrel 40 and into engagement with the cone 49; and the collar 50 replaced and screwed home to clamp the strip end between the cone surfaces 49 and 51.

The fuse is installed upon the movable member of the cut-out by entering its upper end in the loop 37 until it comes up against the bracket 38. The lower end is then swung toward the slab 27 until it enters and is engaged by the clip 36. As the fuse is swung into place one surface of its respective cubical terminals 41 and 4 5 abuts against its receptive ledge 35 and thereby alignment of the terminals 41 and 45 with their respective con-- tact clips 23 is effected accurately and individually since the terminals 41' and 45 are freely adjustable rotarily to each other and any twisting of the insulating barrel 39 due to weather or heat action cannot interfere with the pro er coaction of the fuse terminals with their clips and as a consequence of the good contact connection the contacts do not become over hot in service.

After closing the movable member the latch bolt 18 is turned to secure the members in their relative positions as indicated in Fig. 4 with the lower end of the fuse barrel 40 disposed in the outwardly flaring opening 9 in the bottom wall so that its discharge takes place outside the cut-out.

When an unsafe amount of current flows in the circuit on which the cut-out is installed, the fusible link 52 quickly fuses or volatilizes at its weakest point, at or near the upper end,

and the metallic gases evolved expel themselves under the instantaneously great pressure out through the barrel 40.

This discharge action is often so violent as to create a partial vacuum within which tends to cause the metallic gases to be sucked back into the cut-out and so provide a conductive path for the power are to form and maintain itself from terminal to terminal along the Outside of the fuse barrel, but by reason of the dams 19 and central planel 31 fitting closely about the barrel and effectively isolating the end compartments, together with the action of the baffles 34 to choke any slight entrance of gases past the dams, the arc is prevented from forming between the terminals.

While we have shown and described the best embodiment of the invention known to us, We do not desire to be restricted thereto.

lVhat we claim as new and desire to secure by Letters Patent of the United States is:

1. A primary cut-out comprising pivotally connected housing membersofinsulatiomfuse terminal connections mounted on one of said members, fuse holding means mounted on the other of said members, means for isolating the space about one terminal connection from the space about the other when said members are in closed relation, and a tubular expulsion fuse adapted to engage said terminal connections and extend through said isolating means and a wall of the housing formed by said members.

2. A primary cut-out comprising two pivotally connected housing members of insulation, fuse terminal connections mounted at opposite ends of one of said members, fuse holding means mounted on the other member, a grooved transverse dam on one member and a grooved raised panel on the other member adapted to isolate the spaces about the said terminal connections when said members are in closed relation, and a tubular expulsion fuse adapted to engage said terminal connections and to fit in the grooves of said dam and said panel.

3. A primary cut-out comprising two pivotally. connected housing members of insulation, fuse terminals mounted at opposite ends of one of said members, two spaced and grooved transverse dams located on one member between said terminal connections a grooved raised panel on the other mem er adapted to come adjacent the said dams when said members are in closed position, baffle projections carried by said raised panel and adapted to enter the space between said dams, and a tubular expulsion fuse adapted to engage said terminal connections and to fit the grooves in said dams and panel.

4- A primary cut-out comprising a unitary box-shaped member of moulded insulation having therein contact means for thereception of an expulsion fuse and longitudinal on the outside thereof an integral dovetailed projection, and a correspondingly shaped metal support adapted to be clamped upon said projection and serve to reenforce said member of moulded insulation.

5. A primary cut-out comprisin two housing members of insulation pivota ly connected, fuse terminal connections mounted on one of said members, fuse retaining means mounted on the other member, fuse terminal positioning ledges provided on the latter member, and a tubular expulsion fuse barrel having parallelopiped terminals fixed thereto and independently movable about its axis and adapted to engage said ledges.

6. An expulsion fuse comprising an insulating barrel parallelopiped terminals said terminals being fixedly connected and the other being swivelly connected thereto, and

means for attachment of a fuse link to said terminals.

7 An expulsion fuse comprising an insulating barrel, parallel sided terminals at the ends of said barrel and connected thereto so as to swivel relatively to each other, and means on each terminal for connection of a fuse link thereto.

In witness whereof, we have hereunto set our hands this 18th day of April, 1925.

EDWARD G. NEWTON. ELMER J. WADE. 

